This paper demonstrates the possibility of executing wide band hard real time application in user space under Linux. Such a possibility is demonstrated through examples of its implementation at DIAPM of three digital active control systems, that require relatively high (up to 12 KHz) control frequencies: an active noise control of an acoustic duct using feed-forward techniques, an application of active… (more…)

An open system allows independently developed hard real-time applications to run together with non-real-time applications and supports their reconfiguration at run-time. The open system always accepts non-real-time applications, but it never accepts a real-time application that may not be schedulable in the system. (more…)

Telemetry requires only soft realtime, i.e. receiving data at a fixed high rate without loss . These data must be processed in time and delivered to several different applications. The requirement for being real time is weak, as seen by human eye. Therefore standard LINUX is used with a special driver. (more…)

Real-time Linux variants are being considered for use in safety-critical applications in medicine, aviation, and other areas. The open-source philosophy has much to offer in these applications, but certification concerns impose additional requirements on the verification processes applied to these applications. (more…)

In this paper a remote data acquisition system for Mössbauer Spectroscopy based on RT-Linux is presented. More precisely, a kernel module is in charge of collecting the data from the data acquisition card which is self-made based on ISA, sharing the data with the normal Linux process through the module of mbuff, carrying out the remote control and returning the results to the client by building a simple… (more…)

Some recent discussions in the Linux circle are on the low latency patch posted by Ingo Molnar. There are pros and cons on the usage of preemption points (or “schedule points” in Ingo's terminology). The preemption point approach is to solve the problem that the Linux kernel is non-reentrant. (more…)

GPS, or Global Positioning System, is a key technology for both the civilian and scientific research markets. GPS provides users with precise geodetic positioning and time determination. Most GPS receivers require specialized hardware and complex software to operate. One receiver, known as GPSBuilder-2 originally designed by GEC Plessy, takes a novel approach. (more…)

The Resource Kernel (RK) is an OS-independent kernel abstraction that provides guaranteed, timely and enforced access to system resources including CPU cycles, disk bandwidth and network bandwidth. RK, developed and distributed by the Real-Time and Multimedia Systems Laboratory at Carnegie Mellon University, has been incorporated into the Linux kernel to create a real-time version of the Linux kernel… (more…)

Robot control software is a typical application applying real-time Linux as a hard real-time operating system. The author's software was originally running under MS-DOS. Problems of adapting it for real-time Linux are presented. This paper describes internal structure of the software as it had to be divided into a hard real-time part (a kernel module) and a standard Linux process part. (more…)

This paper describes a set of open source, integrated tools for developing embedded real-time applications, especially targeted to the automotive industry. The set of tools comprises a schedulability analyzer, a kernel library and a kernel configurator. The goal is to achieve portability of the application over different hardware platforms without sacrificing performance. (more…)

This paper presents the design decisions made and architecture used in developing a real time system to control a two-axis positioning gimbal. This system is interesting in that it includes several real-time to non-real-time interfaces for user interaction and network communications. (more…)

ELinux is an extensible version of the Linux operating system capable of runtime extensions with functions that effectively manage the information flows and associated computations across distributed embedded execution platforms. (more…)

Techniques allowing kernel tasks and user space processes to share large blocks of memory are presented. In particular, “mbuff/” device driver is introduced. Simple examples of synchronizing producer and consumer threads using only shared memory are given. (more…)

Comedi is a collection of drivers, common core, and high-level programming interface for data acquisition hardware, including A/D converters, D/A converters, digial I/O, and timer/counters. Comedi is somewhat unique among Linux drivers in that it equally supports real-time and non-real-time applications. (more…)

The rt_com module provides a standard serial port driver for Real-Time Linux. It defines a API to access the generic PC-architecture serial ports from Real-Time space. rt_com works with NMT RT-Linux as well as RTAI. This talk gives an outline of the programming interface as well as of the internal structure of the driver. (more…)